Anode for electrolytic condensers



1953 J. B. BRENNAN 2,648,119

ANODE FOR ELECTROLYTIC CONDENSERS Filed July 24,. 1948 IN V EN TOR.

war 7 Patented Aug. 11, 1953 UNITED STATES PATENT OFFICE ANODE FOR ELECTROLYTIC CONDENSERS Joseph B. Brennan, Cleveland, Ohio Application July 24, 1948, Serial No. 40,610

1 Claim. 1

This invention relates to anodes for electrolytic devices such as electrolytic condensers for example.

This invention is an improvement over the invention disclosed in my U. S. Patent #2,104,018, issued January 4, 1938.

The object of this invention is to produce an anode for electrolytic condensers which is flexi ble, self-supporting and porous throughout substantially all its area and permeable by electrolyte throughout.

The anode so produced according to my invention is so flexible that it can be coiled and folded at 180 angle on itself without fracture.

The anode so produced according to my inven tion has tensile strength sufficient to permit drawing it over several rolls in and out of a formation tank and recoiling it and thereafter rewinding it without fracture.

The anode so produced according to my invention will conduct at least 30 amperes without undue heating continuously.

The anode so produced according to my invention will permit light and gases and paste type fluid electrolyte to pass through its interstitial pores in all directions.

The anode produced according to my invention is composed of a unitary metal such as 99.8 purity aluminum and has a dielectric film over all its area exposed to the electrolyte both external and interstitial and evinces capillarity throughout.

The anode according to my invention is produced in continuous strip form by continuously spray-depositing metal as 99.8% or greater purity aluminum in molten particle form onto a moving non-adhering surface in such a way that the molten metal particles are solidified on deposition and form a continuous band of the so-deposited particles which band has sufficient tensile strength and flexibility to permit peeling the sodeposited continuous band from the moving base onto which it has been deposited continuously. The band of porous capillary material so deposited has preferably substantially uniform gauge in its cross-section and its longitudinal sections so that it is coherent, unitary, self-supporting, flexible, homogeneous and light permeable.

One way of making the continuous flexible strip metal material from which anodes according to my invention are made is to build up the edges of the spray-deposited layer with an additional spray-deposit superimposed on a first spray-deposit and overlapping the edges thereof or to use a series of overlapping spray-deposits and thereafter stripping the so-deposited flexible layer from the base onto which the de posit is made.

Suitable base materials for receiving the spraydeposit comprise anodised aluminum bands or stainless steel bands which are temperature-controlled so as to chill the deposited metal layers upon deposition.

After deposition of the continuous monometal homogeneous unitary elongated porous strip metal layer it is continuously stripped from the base and the so-stripped layer is flexible enough to permit coiling as it is stripped into a continuous coil at least several hundred feet long.

After so coiling the coil thereof is ready for formation and is mounted on a formation machine which draws the so-deposited and coiled flexible band continuously through a formation tank in several passes containing boric acid and having a voltage impressed on the porous continuous flexible band, by means of contacting conductive shoes or rolls and has a dielectric film formed thereon at a constant rate to bring the leakage to a wanted value.

Anodes made according to my invention have a capacity of as much as one microfarad per square inch when .006" thick and are flexible, whereas heretofore anodes made by spray-depositing on fiber bases have been much thicker due to the fact that the base adds unwanted and unnecessary thickness to the anode. Furthermore expense is involved in using fibrous bases such as gauze or paper which expense is eliminated by my invention.

Furthermore contaminating ingredients are frequently and usually present in the fibrous base presently used in making spray-deposited elec trodes and these are eliminated according to my invention.

I also secure a flexible electrode according to my invention which has uniform capacity per unit of area over substantially all its area.

Due to the greater thinners due to the elimination of the fibrous base material heretofore used in making anodes according to my invention a smaller package is required to contain a given unit size condenser, space is saved as well as weight.

Anodes made according to my invention will withstand surges which cause sparking or scintillation better than composite anodes heretofore made because there is nothing in my porous anodes to carbonize and breakdown is less frequent therefor.

Anodes according to my invention may be used in A. C. condensers as well as D. C. condensers.

By mono-metal I mean a relatively pure metal such as 99.9% or 99.8% pure aluminum for example.

By homogeneous I mean having substantially similar constituents throughout, derived from a single source, or essentially alike.

Electrodes made according to my invention evince capillarity when. partially immersed in the usual electrolytes so that the electrolyte if fluid travels above the level of immersion; in other words these electrodes even though entirely metallic in structure absorbelectrolyte within their pores and interstices and even in a zone above the level of the fluid electrolyte when partially immersed The heretofore common belief.

has been that flexible porous electrodes having such characteristics could not be made: except in conjunction with a fibrous base.

In. the accompanying. drawings:

Figure l is a perspective view. of. acondenser roll made from electrodes embodying the princi ples of the invention;

Fig. 2 is a. fragmentary greatly enlarged cross sectional view ofv an electrode. strip of. the. pres.- ent invention.

Figure l of the drawings shows thatvtwo porous metallic strips. I3;.produced in accordance with the invention, may. be. superimposed vwithconven- 4. tional fibrous spacer strips l1 therebetween with such assembly then being formed into a condenser roll l8. Any suitable terminal means may be associated with this condenser l8.

These metal strips B are porous as described hereinbefore and as illustrated in Figure 2.

Having described my invention what I claim is:

Method of continuously producing a homogeneous unitary self-supporting porous flexible electrode strip for electrolytic devices comprising continuously spraying molten metal particles onto a continuously moving base, maintaining the temperature of the base sufficiently low to chill the deposited-metal layer upon deposition, and thereafter stripping the so-deposited material therefrom and thereafter forming a dielectric film thereon.

JOSEPH B. BRENNAN.

References Citedin the ,fileofthis patent- UNITED STATES PATENTS Number Name Date:

2;066;9l2 Ruben: Jan. 5;;1937 2,104,018 Brennan Alan. 43.1 938 2,280fl89 Brennan Apr-28,1942 2,375,211- Brennan -May 8,- :1945 2,404,824 Booe July 30.1946 

